[AMRadio] Thordarson transformer question

[Todd Bigelow - PS]

Thanks to the link that Pete posted earlier, I found the information on 
a mod transformer found at a hamfest a few years back. It's a Thordarson 
Multi-Match model T-11M78, 300-500 watt model. Something puzzles me, 
though - in the listing information it says "Features Thordarson 
Switchboard Plug-in Terminal Board for quick and accurate matching of 
tube loads". Now, I noticed that the terminals didn't have a typical 
threaded screw hole or post like most others, but I have no idea what 
kind of 'plug-in' plugs it uses. Is there anyone out there who could 
shed some light on this matter for me?

Many thanks -
Todd,  KA1KAQ